Hydraulic check



3 Sheets-Sheet 1 H. A. KNOX HYDRAULIC CHECK Filed Jan. e, 1942 Jan. 16, 1945.

Jan. 16, 1945. H. A. KNOX HYDRAULIC CHECK Filed Jan. 6, 1942 3 Sheets-Sheet 2 Hill? 3M Zamw Jan. 16, 1945. H. A. KNOX 'HYDRAULIC CHECK Filed Jan. '6, 1942 5 Sheets-Sheet I5 Q 3mm@ Hurljy A- Knox ZW M W/ ff// MVM/,

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Patented Jan.' 16, 1945 HYDRAULIC CHECK Harry A. Knox, Washington, D. C. Application January 6, 1942, Serial No. 425,717

(Cl. 18S- 88) 2 Claims.

(Granted under the act of March 3, 1883, as

amended'Apl'l 30, 1928; 370 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a suspension for Vehicle Wheels having hydraulic means for checking abnormal movement of the Wheels.

An object of this invention is to provide a resilient wheel suspension incorporating a hydraulic check. Y

Another object of this invention is to provide a resilient supporting means for Wheels of a vehicle incorporating therein apparatus for causing the wheels to have a greater resistance to movement in one direction than in the other.

Another object of this invention is to provide hydraulic means for controlling the movement of the wheels of a track laying vehicle.

Another object of this invention is to provide a wheel suspension for track laying vehicles in which spring means are combined with hydraulic means so as to absorb large amounts of road shock with a relatively small amount of discomfort to the occupants.

Another object of this invention is to provide an improved iluidtight connection between a iluid cylinder and a piston rod.

Another object of this invention is to provide an improved check valve mounted in a piston of a fluid cylinder.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a sectional view taken substantially on line I-I of Fig. 2. Fig. 2 is a plan view of the suspension and hydraulic check and a portion of the supporting means in section.

Fig. 3 is a view taken substantially on line 3-3 of Fig. 1. f

Fig. 4 is a view taken substantially on line 4 4 of Fig. 1.

Fig. 5 is a view taken substantially on line 5-5 of Fig. 1.

Fig. 6 is a plan view of one of the wheel supporting arms detached from the hydraulic check; a portion of the clamping means for contact shaft 25o is shown in section.

Fig. '7 is a View taken substantially on line 1-1 of Fig. 1.

Referring to the drawings wherein like numerals designate like parts, the suspension is adapted to be rigidly flxed to a portion I0 of the vehiclevframe and to carry a pair of wheels II resiliently.

The suspension proper is supported by two brackets I2, I3 which also serve to house the movable portions of the suspension. The brackets I2, I3 are rigidly interconnected by means of two shafts I4, I5 which have their ends rigidly fastened in split hollow portions I2a, |311. (Fig. 3) in the brackets I2, I3 respectively by means of clamping bolts I6 which pass through shaft grooves Ma, I5a. The split hollow bracket portions I2a, I3a are drawn up tight around the shafts I4, I5 by means of nuts I6a respectively; also, shaft grooves I4a, I5a cooperate with the lbody portion of bolts I6 so as to prevent rotationand axial movement of shafts I, I5. The movable portions of the suspension are adapted to oscillate about the xed shafts It, I5.

The movable portion of the suspension may be considered to have four arms Il, I8, I9, 20 which are in pairs II, I3, and I9, 20 so as to be disposed on opposite ends of the volute springs S, S. Arm Il is permanently joined to and spaced from arm I8 by means of a welded connection between those arms and tubular member 2|; similarly arm I9 is permanently joined to and spaced from arm 20 by means of a welded connection between those arms and tubular member 22. Tubular members 2 I, 22 are adapted to receive shafts I5, I4 respectively and to be disposed'vbetween bracket abutments |21), I3b. Elastic material 23, 2d such as' rubber is disposed between shafts I4, I5 and tubular members 2l, 22 in such a fashion, well understood in the art, that relative. movement between the shafts and tubular members is accommodated lby the resiliency of the material 23, 24 respectively.

Each of the arms I1, I8, I9, 20 are of similar construction and have members similar to those of I'Ia, IIb, IIc, I'Id, I'Ie on arm I'I; those members are lettered similarly to those ,of arm I'I in the drawings. Those members serve to join hollow portions similar to those of IIg, IIh, Ilz' and |17' in arm II in aligned relationship so that a shaft passing through one of the arm hollow portions will also pass through a corresponding hollow portion in the other arm which forms a pair with the last mentioned arm.

A pair of volute springs S, S', have their ends abutting against spring seats 25, 26 which have outside channel portions 25a, 26a adapted to receive at contact bars 25h, 26h and cylindrical shafts 25c, 26e respectively. A line contact is thus provided between the last mentioned shafts and their contact bars and in case this line contact is impaired by wear or other causes a new one may be established by loosening clamping screws d, 26d which clamp split hollow arm4 portions |11', |8, |9i, 201 to the ends of shafts 25e, v26?: respectively and then rotating the shafts a small amount; the split hollow portions are then reclamped to the ends of their shafts by screwing clamping screws 25d, 26d in tapped holes 25g, 26g. Tapped hole 25g is shown in section in Fig. 6 and of course tapped hole 25g is of similar structure.

Projections 26e (Fig. 1) on the spring seats 25 project into the hollow of the volute springs and together withnanges 25e (Fig. 3) on spring seat 25 maintain the volute springs S, S' in position. Tapped holes 26j (Fig. 1) in spring seat 23 are made of avail in assembling the suspension. An assembly rod (not shown) is adapted to pass through hole25f in spring seat 25 and to screw lin one of the tapped holes 261 in spring seat 26.

Features of the resilient suspension thus-far described are disclosed in my patent, No. 2,323,919 issued July 13, 1943. This instant application relates more particularly to the features of the hydraulic check alone and in combination with the resilient; suspension thus far described.

The hydraulic check assembly having hardened bushings 29, 29' integral therewith is centrally and rotatably mounted on shafts 21, 29 which are held fast in the arm hollow portions I'lj, |81 and |97', 207' by means of cotter pins I11c, |8k and Ik, 20k, respectively. The hydraulic check has three major parts, i. e., piston 32, the head or closure 30 and cylinder 3|, and those latter two parts are clamped together by means of four circumferentially disposed bolts passing throughfour ears 3| p on the cylinder 3| and engaging tapped portions in the head. A resilient oil resistant gasket may be interposed between those two major portions 30, 3| so as to provide a resilient connection therebetween. The head has a hollow portion 30a having the hardened bushing 29 fastened therein so as to provide a good Wearing surface between shaft 21 and the head 30.

Piston 32 having a pair of ball check valves 31, 38 or similar closure members mounted therein is adapted to move with respect to its cylinder 3| when there is relative movement between the pair of arms I1, I8 and pair of arms I9, 20 since the cylinder 3| is rotatably mounted on arms |1, I8 and the piston rod is rotatably mounted on arms I9, 20 by means of a pin connection 33a between piston rod 33 and the hollow portion 35a of rotatable sleeve 35. A hardened bushing 29' fastened in sleeve 35 is adapted to rotate on hardened shaft 28.

Piston 32 has two types of fluid ports therein, i e, a port 36 having a constant opening and ports of the type adapted to be open only when the wheels of vehicle are quickly raised relative to one another. Two ball `check valves 31, 38 are used in this particular embodiment of my invention although it is understood that under certain conditions one ball check valve having a larger ball therein may be substituted for the two ball arrangement disclosed, or more than oil which leaks through 39 accumulates in cylin-v der hollow portion 43 from where it is returned to the left hand side of the piston through oil two ball check valves may be disposed in the piston. It is desirable to use a plurality of small ball check valves instead of one large one for smooth operation for then 'the composite check valve structure has a smaller opening for a given displacement of the wheels.

The cylinder is filled withoil through an opening-54 in the cylinder head up to the level of the other opening 54' and it is seen that due to the return port or conduit 4| (Fig. 7). The air reservoir B provided in the cylinder head serves as a cushion and an expansion chamber for the oil in the oil chamber A and the stored energy in volute springs S, S' serve to return the piston 32 to the right; however, piston 32 moves to the right more slowly than when it moved to the left because bail check valves 31, 38 prevent the ow of oil to the oil chamber from the compression chamber C to the oil chamber A. The gravitational forces of the uid in the cylinder 30 along with the aircompressed therein tend to increase the forces acting on the end of the piston 32. The flow of oil from the compression chamber C to the voil chamber A occurs through control hole 36 via opening 35a but for any small undesired leakage through 39 and the ball check valves 31, 38. It is fundamental to realize that opening 36 may be made variable although the drawings show opening 36 to have a xed open` ing.

An oiltight joint 45 is provided between the cylinder 3| and vpiston rod 33 at the place of emergence of the piston rod from the cylinder. This joint may be constructed in a manner well known in the art and the one shown herein comprises two oil retainer rings 46, 41 in the cylinder recess 3|a. The retainer rings ll up the space between the cylinder and piston shaft. 33 and are held in the cylinder recess by means of a ring 48.

It is `noted that the pressure on the oiltight joint 45 never reaches the pressure in the compressionchamber C becaused of the snug fit between piston rocl 33 and cylinder hole 39, and the oil return port 4| (Fig. 7); accordingly an elaborate high pressure oiltight joint 45 is not necessary in order that there be no oil leakage from the oil cylinder to the outside,

Balls 50, 5I of check valves 31, 38 fit into rounded seats 52, 53 on the piston 33 so that passage of oil from compression chamber C to oil chamber A through ports 32a, 32h is prevented. The balls 50, 5| may move radially with respect to the cylinder 3| in the radial piston openings 32o and have their motion limited by the inner surface of cylinder 3|. In order to remove the balls from the openings 32e it is necessary to separate the cylinder closure or head 30 from the cylinder 3| and move the piston 32 out of its cylinder 3| whereby the inner surface of the cylinder 3| no longer restrains the balls.

Suitable holes |2e, |3e are provided in brackets I2, I3 for fastening the brackets to a portion of the vehicle by means of bolts, or other similar means.

It-is seen that a suspension and hydraulic check for two wheels of the vehicle are disclosed in the drawings in which each wheel has a common shock absorbing means; but, for purposes of analysis of one phase of applicants invention. it is also seen that each wheel axle has an independent action even though the other wheel is held rigidly and considered to be a portion of the vehicle bracket. l

Also, the wheel axles disclosed may rotate with the wheels or they may be held fast in their supporting frames.

The check valves 31, 38 are shown in the drawings as providing a checkV for the rapid return of the volute spring S, S from a compressed position to` a lesser compressed position. Various changes may be made in the specific embodiment of the present invention Without departing from the spirit thereof, or from the scope of the appended claims.

I claim:

1. A fluid cylinder with avdouble-acting piston therein having a radial recess, passages in said piston communicating with said radial recess from both sides of said piston, a check valve in said radial recess adapted to close one of said communicating passages upon the rebound movement of the piston, an auxiliary valve-free passage through said piston and establishing communication with the cylinder on both sides of the piston, a partition in said cylinder near one end thereof and forming a chamber with said end, a piston rod slidably passing through said partition, and a uid connection from said chamber to the other end of said cylinder, and a hollow head disposed above the other end of said cylinder in communication therewith and adapted to form an air chamber.

2. A hydraulic damper comprising, in combination, a cylinder, a piston therein having two apertures passing therethrough, a check valve in one of said apertures, a partition in said cylinder forming a chamber, a piston rod passing through said partition, a fluid connection between said chamber and the opposite end of s aid cylinder, and a hollow head disposed above the end of said cylinder opposite said chamber and in communication therewith for fluid overflow and air.

` HARRY A. KNOX. 

